ArcGIS Pro: Polyline Symbology error: "Requested operation could not be completed"

[ElieRizk]

The issue persists in AGP 3..3.1 it is a show stopper to work with complex symbology for polyline layers. we are not able to move forward with such behavior. it is noted, the issue faced when using a feature class stored in file geodatabase and enterprise geodatabase.

we tried the steps mentioned in the following ESRI technical support page without success.https://support.esri.com/en-us/knowledge-base/error-requested-operation-could-not-be-completed-00002...

Also, someone mentioned that ESRI categorized this issue as a bug, but we aren't able to find the bug number.

"@ABishop kindly can you head up to the number of the bug mentioned in the URL you inserted in your message?

Here is a link to the BUG report site: https://support.esri.com/en/Search-Results#search?q=arcgis-pro&content-type=Bugs"

thank you,

ER,

[IanMott1]

This worked for me but it would be very nice if it didn't need to happen. Please fix this bug in 3.3 Esri! I work for a large Enterprise company that isn't on 3.4 yet.

[LarkinPhil]

Update: my workaround was to create the symbology in 3.5 and import it via a layer in 3.3.5.

I am experiencing this problem in Pro 3.3.5. I have a point layer using Graduated Colors Symbology. Each class has two symbol layers. When setting the properties of the second class the 'Requested operation could not be completed' shows up. 

1 of 4 classes set, working on the 2nd class:

Attempt to create a new symbol layer on second class: